“…Direct application of this approach relies on measured direct feedback from the individual plant species and measured microclimatic and environmental parameters. This approach involves measurement or modeling of stomatal resistance ( r L ) and other primary environmental variables and requires scaling up r L to canopy resistance ( r c ) using microclimatic and plant factors such as leaf area index (LAI) for sunlit and shaded leaves, solar zenith angle, direct and diffuse solar radiation above and within the canopy, and other environmental parameters [ Kaufman , 1982; Jarvis and McNaughton , 1986; Rochette et al , 1991; Lhomme et al , 1998; Jones , 1992; Tourula and Heikinheimo , 1998; Furon et al , 2007; Irmak et al , 2008; Irmak and Mutiibwa , 2010; Mutiibwa and Irmak , 2011]. The scaling‐up process primarily relies on scaling up r L to r c as a function of solar radiation, net ration, or photosynthetic photon flux density (PPFD).…”